In college my grade in physics was forgettable, so when I set out to understand just exactly we had on our shelves for springs, it became quite a project. We started off with a simple premise. How close really are the aftermarket versions we’re carrying for 9-3 replacement springs to what SAAB is now selling for the same suspension codes? We used the top three varieties of replacement spring and put them to the test: 9-3 with standard suspension and manual transmission (SAAB OE 93190594), 9-3 with a standard suspension and an automatic transmission (SAAB OE 93190595) and a 9-3 with a sport suspension package (SAAB OE 93190608).
In order to fully understand the results you first have to delve into the mystery of what a coil spring is, and what it does in the system of your car’s suspension. A coil spring starts off as straight wire, which is heated, wrapped around a mold, and then tempered. The wire, based on a variety of factors, has an elastic tendency (or desire) to return to its original (coiled) shape when stretched or compressed.
The force that a spring exerts is static as it stretches and compresses is a constant rate. That theory is called Hooke’s Law. Hooke’s law states that the force that a spring exerts is constant until it’s elastic limit is reached – basically the spring has been completely straightened or the spring has been completely compressed, commonly called bound – at which point the spring rate approaches infinity. What this means for us is that, for the most part, a spring exerts the same amount of force for each inch it is compressed or extended or better translated it holds the same amount of weight.
Most of the springs in our cars now are actually progressive, which means that the spring rate is less to start and increases slightly as the spring compresses. For the purposes of this exercise we more or less ignore the progressive changes because the springs are so close in rate. So where are we finally with our 9-3 front springs?
What we found is that the our current “aftermarket” varieties are very close to the “new” original versions. Additionally the “rates” are so close as to be essentially interchangeable. The only significant difference is that the “Sport” springs are 1.25 inches shorter than the stock non-sport versions. This will probably ultimately result in a drop of .75-1 in on your front end when paired with the correct shocks.
See below for complete information. All springs were tested for rate between the 2nd and 3rd inch of compression. Stay tuned for Pt. 2, where we take a look at differences in aftermarket performance springs designed for sport use and lowered ride height.
|OE #||Part Code||Brand||Retail Price||Spring Rate||Starting Height|
|93190594||93190594X||eEuro Preferred||$26.99 (ea) Pair Only||125||13.50|
|93190594||32016015||Original SAAB||$63.99 (ea) Pair Only||125||14.00|
|93190595||32016017||Original SAAB||$64.49 (ea) Pair Only||145||14.00|
|93190608||32016016||Original SAAB||$68.49 (ea) Pair Only||155||12.75|